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Eucalyptus marginatais an aromatic and medicinal plant species used in several industrial sectors, owing to the chemical properties of its essential oil. The present study aimed to evaluate the chemical composition and antioxidant activities of Eucalyptus marginataleaves collected in three seasons of the year (winter, spring and summer). Therefore, essential oil yields, total phenolic, flavonoid, tannin and chlorophyll contents have been evaluated. Essential oil chemical composition was carried out by combination of GC-FID and GC–MS. While, individual phenolic quantification has been done using LC–ESI–MS. This study demonstrated that spring seasons presented the highest contents of total phenolic compounds (491.01 mg GAE/g DW), chlorophyll α (134.55 mg/g DW), chlorophyll β (216.61 mg/g DW), chlorophyll α + β (350.61 mg/g DW), DPPH (1.099 mg/g DW) and ABTS (0.909 mg/g DW). The major compounds of Eucalyptus marginataessential oil for the three seasons were 1,8-Cineol (22.42 − 30.52%), while, the quantification of the identified phenolic compounds showed a significant difference between the three season (p< 0.05). Results revealed that Eucalyptus marginatais a nature source of compounds with antioxidant proprieties, and the difference in chemical composition leads to change in the antioxidant activity of plant, which contributes to seasonal change.

Changes in quality parameters of flavored/aromatized Chemlaliolive oil by the green addition of Verbena officinalisL. phenolic-rich extract were studied as a function of storage time (6 months) at room temperature (20 °C). Evaluation of oil quality was established by studying the FA, PV, K232, K270parameters, as well as chlorophyll and carotenoid contents, total phenolic and flavonoid content (TPC and TFC, respectively). Results showed that chlorophyll and carotenoid pigments decomposed, respectively, for more than 30 and less than 24% in the flavored/aromatized oil samples stored at 20 °C. Additionally, the decreasing rate of phenolic and flavonoid content in the flavored olive oil was lower than that in the control samples. These findings proved that aromatization with Verbena officinalisL. phenolic-rich extract obtained after optimisation of microwave parameters may be an alternative to improve olive oil quality and create a new competitive flavored product.

Phytochemicals, such as phenolic compounds, are of great interest due to their health-benefitting antioxidant properties and possible protection against inflammation, cardiovascular diseases and certain type of cancers. Maximum retention of these phyto-chemicals during extraction requires optimized process parameter conditions. Verbena officinaliswas treated using “green” technic and “green” solvent by elaboration of an efficient alternative protocol in order to obtain a phenolic rich extract.A microwave-assisted extraction (MAE) method was investigated to obtain high phenolic compounds content from this plant with high antioxidant activities. The main studied extraction parameters were: time (t: 5 to 25 min), irradiation power (P: 150 to 750 W), liquid-to-solid ratio (R: 10 to 50 mL g−1) and pH (pH: 3 to 7). A microwave-assisted extraction showed that the best performance, resulting in an extract with phenolic and flavonoid contents (94.48 mg GAE/g DW and 64.07 mg QE/g DW, respectively), a DPPH and FRAP says (23.99 µg/ml and 997.46 µM of BHT/g DW, respectively). The optimal conditions were: extraction time = 15 min, microwave power = 550 W, solvent pH equal to 5.5 and liquid-to-solid ratio = 39 ml/g. To our knowledge, the polyphenolic rich extract has been analyzed using UPLC-HRMS apparatus which allowed us to identify seven phenolic compounds: verbascoside, isoverbascoside, hydroxytyrosol glucoside and four flavonoid compounds including: Cirsilineol, Catechine (+),Naringenin and quercetin-3-O-rutinoside. Results showed that this innovative and green extraction method (microwave extraction) can be used successfully to obtain bioactive compounds in higher amounts from Verbena officinalis.

Leucaena leucocephala(Lam de wit) is a valuable source of bioactive metabolites with high preventive and therapeutic effectiveness. Here, and taking into account the effect of geographical location and maturation stage, we aimed to investigate the chemical composition of phenolic, fatty acid profiles (GC-FID) and biological activities from L. leucocephala(Lam de wit) seed oil and leave extracts. The results indicated that L. leucocephala(Lam de wit) ethanolic leaves extracts growing in Ariana have the highest levels in phenolic and flavonoid contents and showed remarkable antioxidant activities. Furthermore, L. leucocephala(Lam de wit) oils extracted from seeds growing in two locations at different maturation stage were analyzed using GC-FID to determine fatty acids profiles and significant differences (p< 0.05) were observed between growing area and maturation stage. In addition, both oils and ethanolic extract of L. leucocephala(Lam de wit) were able to limit gram positive and gram negative bacteria, Candidaspecies as well as the tested filamentous fungi species, and the examination of results prove that the diameter of zone inhibition was related to the tested microorganisms. The results credibly indicate that L. leucocephala(Lam de wit) leaves and seeds are nutrient-rich and can contribute effectively to the daily nutrient requirements alongside its therapeutic properties.